Yep I've had my RNS 310 installed for over 2 months and had no battery drain issues whatsoever. 2006 GTI with the original CAN Gateway (1K0 907 530 F).
Its a really nice unit and suits the car well, excellent value for money too. I'm running the 2012 maps on mine which support full 7-digit postcodes. Also integrates properly with the Highline display and MFSW, no VCDS coding required. Would 100% recommend
The Parrot kit should still work but you might need to change round the Mute pin at the rear of the quadlock, I need to do the same with my Bury kit at some point. Not sure on the CD Changer but I can't see why it wouldn't work.